The present invention relates generally to video recording, and, more particularly, to a system for storing and displaying xe2x80x9cthumbnailxe2x80x9d images representative of the contents of a video recording medium, thereby enabling a user to locate a particular section rapidly and conveniently.
As the popularity of video cassette recorders (VCRs) has spread, many users have amassed extensive libraries of recordings, representing a wide range of program materials collected over an extended period of time. In most cases, users are faced with the alternative of either maintaining detailed records as to the contents of individual tapes, or sorting through an entire collection until a desired tape is found. Since the rigorous cataloging of tapes has little appeal to users, most users simply resort to notes affixed to individual cassettes, or they write descriptive information on a tape label. However, once the number of tapes in a library exceeds ten or fifteen units, this method for marking becomes unmanageable. Moreover, in the future, new, more compact, video recording media, such as smaller cassettes, magnetic disks, and recordable optical discs or xe2x80x9cvideodiscs,xe2x80x9d are likely to make such marking methods increasingly impractical.
In contrast to existing video indexing arrangements which are text-based, this invention uses pictures representative of a recorded video program to assist a user in determining the contents of a recorded medium. The use of pictures enables the index to be generated automatically from the recorded program material itself, thereby minimizing or eliminating the need to enter textual or other identifying information. Not only is suitable picture information already available in the program material being recorded, but it also is clear that even a small number of pictures may convey significant detail about the contents of a particular program.
Broadly, given a video program to be recorded, a method of indexing that program in, accordance with the invention, includes the steps of separately storing picture-based information representative of the program and later displaying the picture information without having to view the program itself. An index according to the invention may be generated after as well as during the recording process. Considering a video program as a sequential set of images, the invention prescribes separately storing information representative of a small subset of the images and displaying images from this subset as a method of identifying the contents of the video program. Preferably, the pictures represent periods of the program which are separated in time, enabling a relatively few such pictures to characterize an otherwise lengthy program. By way of example, 12 pictures, each representing segments in the program which are spaced apart in time by 10 minutes, may be used to identify and/or index a 2-hour movie. The same display device used for viewing the program material may be used to display the pictures, which preferably are presented in separate windows on the screen. In alternative embodiments, the pictures may include still or moving imagery and, as a further option, the viewer may select a particular picture to commence replay of the recorded program material associated with the picture selected, or initiate playback of stored audio information associated with the picture selected as part of identifying the chosen program segment.
The picture information may be stored on the same medium as that used to record the video program, or a different medium may alternatively be used. To reduce storage requirements, the information is preferably data compressed then de-compressed for display purposes. To derive the information used to generate the pictures, the video program may be sampled on a periodic basis or distributed and received with integrated encoded picture information, which then may be stored separately.
To ensure that the pictures themselves adequately represent the recorded program, aspects of the program may be analyzed prior to the extraction of the picture information to ensure that blank segments, commercials, or other unwanted information is not stored inadvertently, instead of pictures representative of program subject matter. As a further aid to the characterization of a recorded program, the system may automatically store pictures associated with the beginning and/or ending of a particular program or recording session.
In terms of apparatus, the invention may either incorporate a video recorder and a display device, or alternatively, use existing equipment, such as a VCR or disc drive, for recording purposes. A television monitor, computer screen or any other suitable display device may be used for viewing. In conjunction with such hardware, the inventive system includes an input for receiving a video program to be recorded by the video recorder, means for deriving and storing pictures representative of time-separated segments of the program, and means for formatting the stored pictures for viewing on the display device. In a comprehensive embodiment, the hardware includes a picture memory (such as a battery-backed-up random-access memory) for storing the images associated with each of the time-separated segments of the program, a frame buffer in communication with the picture memory and display device, and video display generation means for outputting the contents of the frame buffer to the display device in the form of a video signal.
To convey motion in different windows on the display device, the picture memory stores not one but a series of images associated with each of the time-separated segments of the program, and further includes means for periodically updating the frame buffer with individual images from a particular group, so as to convey motion. In this embodiment which supports moving pictures in multiple windows, a multi-channel tuner may be added and sequenced so that pictures representative of the video programs available on each of the tuned channels will appear in the separate windows, rather than indexing information.